Here is a shortcut to the research you need to determine which solution is best for you.
Sybase
Sybase is still a major force in the enterprise market after 25 years of success and improvements to its Adaptive Server Enterprise product. Although its market share dwindled for a few years, it's returning with powerful positioning in the next-generation transaction processing space. Sybase has also thrown a considerable amount of weight behind the mobile enterprise by delivering partnered solutions to the mobile device market.
PostgreSQL
PostgreSQL, the world's most advanced open source database, hides in such interesting places as online gaming applications, data center automation suites and domain registries. It also enjoys some high-profile duties at Skype, Yahoo! and MySpace. PostgreSQL is in so many strange and obscure places that it might deserve the moniker, "Best Kept Enterprise Database Secret." Version 9.0, currently in beta, will arrive for general consumption later this year.
Teradata
Have you ever heard of Teradata? If you've built a large data warehouse in your enterprise, you probably have. As early as the late 1970s, Teradata laid the groundwork for the first data warehouse -- before the term existed. It created the first terabyte database for Wal-Mart in 1992. Since that time, data warehousing experts almost always say Teradata in the same sentence as enterprise data warehouse.
Informix
Another IBM product in the list brings you to Informix. IBM offers several Informix versions -- from its limited Developer Edition, to its entry-level Express Edition, to a low-maintenance online transaction processing (OLTP) Workgroup Edition all the way up to its high-performance OLTP Enterprise Edition. Often associated with universities and colleges, Informix made the leap to the corporate world to take a No. 1 spot in customer satisfaction. Informix customers often speak of its low cost, low maintenance and high reliability.
Ingres
Ingres is the parent open source project of PostgreSQL and other database systems, and it is still around to brag about it. Ingres is all about choice and choosing might mean lowering your total cost of ownership for an enterprise database system. Other than an attractive pricing structure, Ingres prides itself on its ability to ease your transition from costlier database systems. Ingres also incorporates security features required for HIPPA and Sarbanes Oxley compliance.
